JPH1153487A - Method for deciding validity of written data on ic card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent malfunction by writing one item data sent from a reader writer in write areas individually and successively and deciding whether or not write data match each other. SOLUTION: The reader writer compares received data in three areas 1 to 3 (S12) and judges that the last writing is normally completed when they all have the same contents. When the IC card is used next, the data in the three areas 1 to 3 are compared and if the data contents of the 1st area 1 are different from those of other areas 2 or 3 or if the data are destroyed (S13), it is judged that an abnormal process is done during the writing to the 1st area 1 of the internal memory. If the data contents of the 2nd area 2 are different from those of the areas 1 or 3 or if the data are destroyed (S15), it is judged that an abnormal process is performed during the writing to the area 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for judging the validity of write data in an IC card used for an ID card, a commuter pass, a prepaid card, and the like. The present invention relates to a write data validity determination method suitable for a non-contact type IC card capable of repeatedly reading and writing data.

[0002]

2. Description of the Related Art Recently, various types of non-contact type IC cards have been provided. Among them, there is a type in which a built-in memory in an IC card is accessed by weak electricity induced by a so-called electromagnetic induction method without incorporating a battery. In this type, the reader /
While bringing the IC card close enough to the writer,
If this approach state is not maintained for a certain period of time, writing or reading may become abnormal. For example, as for writing, if the IC card is removed from the reader / writer while data is being sent from the reader / writer and the data is being written to the internal memory, it is not sufficient to access the internal memory. In some cases, power cannot be obtained, and the data writing process fails, resulting in data corruption.
In this case, the IC card itself becomes unusable,
It may cause malfunction of the system using the card.

In some cases, the writing of data is completed, but the IC card is separated from the reader / writer before or during transmission of a response to the reader / writer that the data writing has been completed normally. In this case, the next time the IC card is used, the reader / writer or the host computer managing the system may not be able to determine whether or not the IC card has normal data written therein.

[0004]

The above problems are caused by the operation of the user of the IC card.
Due to the nature of the non-contact type, it is practically impossible to completely eliminate the writing or reading abnormality as described above.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a write data validity determination method suitable for determining whether write data is abnormal due to an operation of a user of an IC card.

[0006]

According to the present invention, in an IC card capable of repeatedly reading and writing data to and from a built-in memory, data of one item sent from a reader / writer is stored in the built-in memory. The first / second / third writing areas of the memory are written individually and continuously, and the next time the IC card is used, the reader / writer writes the first / third writing areas. The validity of the write data is determined by reading the written first, second, and third write data and determining whether there is a match between the first to third write data. A method for determining the validity of write data in an IC card is provided.

More specifically, in the write data validity determination method according to the present invention, it is preferable that at least two write operations are performed on the first to third write areas. When the first to third write data are all the same, it is determined that the first to third write data are valid, and only the second write data and the third write data are the same. At one time,
Determining that the first write data is abnormal; determining that the first write data is valid when only the first write data and the third write data are the same; When only the first write data and the second write data are the same, it is determined that the third write data is abnormal.

When only the second write data and the third write data are the same, the second write data
It is determined that the first write data and the third write data are the data written in the access two times before, and when only the first write data and the third write data are the same, the first write data Is determined to be data written in the previous access, and the first write data is reproduced. When only the first write data and the second write data are the same, at least the first write data is read. Is determined to be the data written in the previous access, and the first write data is reproduced.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION
This will be described with reference to the drawings. FIG. 1 is a memory map of a nonvolatile memory (hereinafter referred to as a built-in memory) built in the IC card. FIG. 2 shows a procedure for writing data to the built-in memory of the IC card. 9 is a flowchart for determining whether or not data writing to a built-in memory has been effectively performed.

In FIG. 1, an IC card that has received a write command transmitted from a reader / writer and data to be written to a built-in memory includes a designated area 1 of the built-in memory and two succeeding areas 2 and 3 in total. Write the same data continuously to the area. Note that such a storage area is an area in which write data is rewritten, that is, updated, in consideration that writing or reading is repeatedly performed each time the IC card is used. Rewriting may be performed in either a byte unit or a record unit consisting of several bytes.

In FIG. 2, when the IC card approaches the reader / writer, it is assumed that the reader / writer transmits data "A" and a write command instructing to write the data "A" (step S1). The process of data transmission and reception between the IC card and the reader / writer up to this state is well known, and a description thereof will be omitted.

The IC card which has received the write command and the data "A" (step S2) writes and verifies the data "A" in the area 1 described in FIG. 1 (step S3). A response signal indicating this is transmitted (step S4). Hereinafter, the same data “A” is written to the areas 1 to 3 twice, twice in the steps S5 to S8.

In FIG. 2, a response signal is transmitted to the reader / writer every time writing and verification of the first area 1 and the second area 2 are completed. Signal transmission may be omitted.

Next, a method for determining the validity of write data will be described with reference to FIG. The determination of the validity of the write data according to the present invention is performed by the reader / writer when the IC card is used next time. At the next use of the IC card, all the data written in the areas 1 to 3 are read and transmitted to the reader / writer.
The process of data transfer between the IC card and the reader / writer up to this state is also well known, and a description thereof will be omitted.

In step S11, the reader / writer performs initialization, that is, resets the CPU in the IC card, checks the internal memory, checks the I / D, and the like. The reader / writer receives the three areas 1-3
Are compared (step S12), and if the contents are all the same, it is determined that the previous writing has been normally performed.

Next, a description will be given of a data validity judging operation for an IC card for which writing has not been correctly performed because the IC card was separated from the reader / writer while data was being written to the built-in memory. Next I
When using C card, compare the data of three areas 1-3,
If the data content of the first area 1 is different from the data content of the other area 2 or 3, or if the data is corrupted (step S13), an abnormal process is performed during the writing to the first area 1 of the internal memory ( (When the IC card is separated from the reader / writer), and determines that the data has not been rewritten. Since the second and third areas 2 and 3 have not been rewritten in the previous write operation, to reproduce the data, refer to the data in the second and third areas. By doing so, it is possible to reproduce the data before rewriting, that is, the data written two times before (step S14).

Next, if the data content of the second area 2 is different from the data content of the other areas 1 and 3 or if the data is broken (step S15), the data is It is determined that abnormal processing has been performed. Here, it can be seen that the data in the first area 1 is data after being rewritten by the previous write operation, and the data in the third area 3 is data that has not been rewritten by the previous write operation. That is, it is the write data two times before. Therefore, in order to reproduce the data, the rewritten data can be reproduced by referring to the data in the first area 1 in which the rewriting has been successfully completed (step S16).

Next, if the data content of the third area 3 is different from the data content of the other areas 1 and 2 or if the data is corrupted, an abnormal process has occurred during the writing to the area 3. Judge that What is understood here is that the first and second data are data after being rewritten by the previous write operation. Therefore, data can be reproduced by referring to either the data in the first or second area 1 or 2 in which the rewriting has been successfully completed (step S17).

As is apparent from the above description, the gist of the present invention lies in a method for determining the validity of data written in a built-in memory of an IC card, and how the determination result is used is described in the present invention. It is outside the scope of the invention.

Although the above description is for a non-contact type IC card, the present invention is also applicable to a contact type IC card. This is true even for contact type IC cards.
In the case of the type that receives power supply from the reader / writer side, the contact time is too short, in other words, there is a possibility that the IC card is removed by the IC card user without maintaining sufficient contact. is there.

[0021]

As described above, according to the present invention,
While writing data to the internal memory, the reader /
Even if the IC card is separated from the writer, it is possible to provide a validity determination method capable of confirming the validity of the write data and reproducing the write data.

[Brief description of the drawings]

FIG. 1 is a diagram showing a memory map of a built-in memory in a preferred embodiment of an IC card according to the present invention.

FIG. 2 is a flowchart for explaining a data writing procedure according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a procedure for describing a method of determining validity of write data according to the embodiment of the present invention.

Claims (3)

[Claims] 1. An IC card capable of repeatedly reading and writing data to and from a built-in memory, wherein data of one item sent from a reader / writer is written to first, second, and third data in the built-in memory. The writing is performed individually and continuously in the writing area of the IC card, and at the next use of the IC card, the reader / writer
The first, second, and third write data written in the first to third write areas are read, and writing is performed by determining whether or not there is a match between the first to third write data. A method for determining the validity of write data in an IC card, which comprises determining validity of data. 2. The method according to claim 1, wherein the first to third write areas are written at least twice, and When all the third write data are the same, it is determined that the first to third write data are valid, and when only the second write data and the third write data are the same, Determining that the first write data is abnormal, and determining that the first write data is valid when only the first write data and the third write data are the same; When only the first write data and the second write data are the same, it is determined that the third write data is abnormal. Effectiveness determination method. 3. The method for determining validity of write data according to claim 2, wherein when only the second write data and the third write data are the same, the second write data and the third write data are the same.
It is determined that the first write data and the third write data are the data written in the access two times before, and when only the first write data and the third write data are the same, the first write data Is determined to be data written in the previous access, and the first write data is reproduced. When only the first write data and the second write data are the same, at least the first write data is read. Wherein the first write data is reproduced by judging that the write data is the data written in the previous access, and a method of judging the validity of the write data in the IC card.